Had similar when I moved here and replaced with the solar glass. It was the full roof (so they replaced the framework too) and I also installed roller blinds. I love the roof and it is cooler during the summer and I am using it unheated in the mornings now. I went glass as I just love the light and its lovely to sit in at night. I heat mine via an electric heater and it warms up fairly quickly and keeps the heat better than it did with the poly carb.